Detection of porcine endogenous retrovirus:: Possible involvement in pig islet xenotransplantation

One requirement prior to xenotransplantation of porcine islets during Type 1 diabetes is to eliminate the risk of transmitting infectious agents, particularly retroviruses, even when specific pathogen-free (SPF) pigs are used. We developed two sensitive complementary PCR-derived detection tests to assess this risk. The first is intended to detect a novel endogenous retrovirus pol sequence related to a recently described human endogenous retrovirus (HERV-L) and to foamy retroviruses. Primers for species-specific detection of this porcine endogenous sequence were designed and tested. The second test is a product-enhanced reverse transcriptase (PERT) assay optimised for the detection of porcine reverse transcriptase activity. These tests, which were used to detect HERV-L-related sequences and reverse transcriptase activity in certain SPF pig cells and porcine cell lines, may be useful in studying the risk of transmitting retroviruses by pig islet xenotransplantation in the immunogenetic context of Type 1 diabetes.